Evaluation of entrainment velocity induced by wind stress in a two-layer system

Abstract

This study aims to reveal the factors most useful for evaluating the influence of wind on entrainment from the lower to upper layer in a two-layer system. Lake Abashiri, which is a typical brackish lake, is chosen as a study area because a distinct two-layer system exists due to salt-wedge intrusion from the ocean. To evaluate entrainment velocity between two layers, a 3D numerical computation is applied, showing good agreement with field observations. Computations suggest that the entrainment velocity estimated using the Richardson number is smaller than that from field observations. Thus, other factors are computed suggesting that use of the Lake number is more effective in estimating entrainment velocity due to internal wave breaking and interfacial fluctuation than use of the Effective Wedderburn number.